Bronze is for people who just want a race licence the cheapest way possible, surely?
No cos you can’t get a Racing Licence with Bronze (well, you get a Provisional one but still have to pay extra “Day Licence” money anyway).
Bronze is essentially there for event organisers and officials (Commissiares, NEG etc). It gives the minimum possible level of insurance for organisers which is why it’s so cheap.
If you’re planning on (road) racing seriously, you need a Silver or Gold, Bronze is useless to you for racing.
Have a look at:
http://www.britishcycling.org.uk/membership and for racing and Day Licences look here:
http://www.britishcycling.org.uk/road/article/roa20120127-road-Single-Day-Racing-Licences-%E2%80%93-Road—Track-0
You can see that even with a Bronze, if you want to do a road race, you’re still coughing up Day Licence money.